Takes place in the same continuity as the original Godzilla series, according to Toho Co., Ltd.
The last appearances of the original King Ghidorah and Gigan (who would return in updated form 31 years later in Godzilla: Final Wars (2004)).
Godzilla guest-stars in Episodes 4, 11, 15, 21 and 25. Gigan fights with Godzilla in Episode 11, and King Ghidorah appeared in a separate two episodes (5 & 6, a two-parter).
King Ghidorah is the only giant monster not killed during the entire series (not including Godzilla, of course).
Already having began as special effects director just a few years earlier with the Crazy Cats comedy adventure film, Dai bakuhatsu (1969), this was the first time Teruyoshi Nakano directed special effects for a TV series.